首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   58539篇
  免费   4727篇
  国内免费   482篇
耳鼻咽喉   963篇
儿科学   1060篇
妇产科学   1067篇
基础医学   9489篇
口腔科学   1067篇
临床医学   5412篇
内科学   11323篇
皮肤病学   1996篇
神经病学   5186篇
特种医学   3182篇
外科学   7179篇
综合类   533篇
现状与发展   1篇
一般理论   18篇
预防医学   3592篇
眼科学   1513篇
药学   5258篇
中国医学   528篇
肿瘤学   4381篇
  2023年   264篇
  2022年   621篇
  2021年   1693篇
  2020年   878篇
  2019年   1343篇
  2018年   1556篇
  2017年   1213篇
  2016年   1766篇
  2015年   2267篇
  2014年   2758篇
  2013年   3193篇
  2012年   4638篇
  2011年   4426篇
  2010年   2706篇
  2009年   2266篇
  2008年   3237篇
  2007年   3176篇
  2006年   2868篇
  2005年   2686篇
  2004年   2286篇
  2003年   1997篇
  2002年   1802篇
  2001年   1183篇
  2000年   1119篇
  1999年   929篇
  1998年   422篇
  1997年   377篇
  1996年   315篇
  1995年   308篇
  1994年   255篇
  1993年   272篇
  1992年   625篇
  1991年   645篇
  1990年   556篇
  1989年   601篇
  1988年   595篇
  1987年   586篇
  1986年   498篇
  1985年   500篇
  1984年   399篇
  1983年   327篇
  1982年   244篇
  1981年   223篇
  1980年   199篇
  1979年   302篇
  1978年   260篇
  1977年   186篇
  1974年   203篇
  1973年   220篇
  1972年   174篇
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
41.
42.
43.
The present study investigated the role of central metabotropic glutamate receptors (mGluRs) in interleukin-1beta (IL-1beta)-induced mechanical allodynia and mirror-image mechanical allodynia in the orofacial area. Experiments were carried out on male Sprague-Dawley rats weighing 230 to 280 g. After administration of 0.01, 0.1, 1, or 10 pg of IL-1beta into a subcutaneous area of the vibrissa pad, we examined the withdrawal behavioral responses produced by 10 successive trials of an air-puff ramp pressure applied ipsilaterally or contralaterally to the IL-1beta injection site. Subcutaneous injection of IL-1beta produced mechanical allodynia and mirror-image mechanical allodynia in the orofacial area. Intracisternal administration of CPCCOEt, a mGluR1 antagonist, or MPEP, a mGluR5 antagonist, reduced IL-1beta-induced mechanical allodynia and mirror-image mechanical allodynia. Intracisternal administration of APDC, a group II mGluR agonist, or L-AP4, a group III mGluR agonist, reduced both IL-1beta-induced mechanical allodynia and mirror-image mechanical allodynia. The antiallodynic effect, induced by APDC or L-AP4, was blocked by intracisternal pretreatment with LY341495, a group II mGluR antagonist, or CPPG, a group III mGluR antagonist. These results suggest that groups I, II, and III mGluRs differentially modulated IL-1beta-induced mechanical allodynia, as well as mirror-image mechanical allodynia, in the orofacial area. PERSPECTIVE: Central group I mGluR antagonists and groups II and III mGluR agonists modulate IL-1beta-induced mechanical allodynia and mirror-image mechanical allodynia in the orofacial area. Therefore, the central application of group I mGluR antagonists or groups II and III mGluR agonists might be of therapeutic value in treating pain disorder.  相似文献   
44.
To assess the relationship between the DSM-III criteria for attention deficit disorder with hyperactivity (ADDH) and the DSM-III-R criteria for attention-deficit hyperactivity disorder (ADHD), children from an inner city parochial school were evaluated using a 30-item teacher questionnaire consisting of the DMS-III and DSM-III-R criteria for these disorders, the revised Conners Parent and Teacher Questionnaires, and a continuous performance test. Diagnostic groups were established based on teacher ratings of the DSM items and evaluated in relation to the rating scale data and continuous performance test. While children who were identified by teachers as having ADDH almost always satisfied the criteria for ADHD, a new group of children who were hyperactive and impulsive but less clearly inattentive also met the criteria for ADHD. Implications of the change in diagnostic criteria are discussed.  相似文献   
45.
OBJECTIVE: To evaluate the factors that influence the outcome of bronchial arterial embolisation (BAE) in chronic tuberculosis (TB). In cases of chronic TB, non-bronchial systemic arteries (NBSA) provide a significant source of massive or recurrent haemoptysis. DESIGN: Medical records and radiological findings of 30 consecutive TB patients who underwent BAE were retrospectively analysed and compared with those of 19 bronchiectasis patients. RESULTS: Chronic TB patients had higher numbers of total feeding vessels (4.40 +/- 3.85 vs. 1.79 +/- 1.51, P = 0.007) and NBSA (1.57 +/- 1.63 vs. 0.42 +/- 0.61, P = 0.005) than the bronchiectasis patients. The number of embolisations required for obliterating feeding vessels (3.87 +/- 2.48 vs. 1.95 +/- 1.47, P = 0.004), and the incidence of incomplete embolisation (30% vs. 5.3%, P = 0.033) were also higher in the TB patients. Moreover, recurrence after BAE was more frequent in the TB patients (17/30, 56.7% vs. 5/19, 26.3%, P = 0.037). Male sex, past history of haemoptysis and incomplete embolisation during BAE were associated with higher recurrence of haemoptysis in chronic TB patients. The existence of a fungus ball or significant pleural thickening (>/=10 mm) was not found to influence the recurrence rate of haemoptysis. CONCLUSION: The haemoptysis recurrence rate was higher in chronic TB than in bronchiectasis; this was found to be related to incomplete feeding vessel embolisation.  相似文献   
46.
OBJECTIVES: This study sought to characterize epileptic phenotypes in children with nonspecific mitochondrial disease (MD) and to evaluate MD diagnostic approaches. METHODS: A retrospective analysis of the medical, electroencephalogram, and laboratory records of 142 patients with epilepsy was performed. The patients were evaluated for MD, and 124 patients were included in the final cohort. The MD criteria used included an oral glucose lactate stimulation test (OGLST) and urine organic acid/plasma amino acid (UOA/PAA) assays as metabolic indicators of modified Walker criteria, as suggested by Bernier et al. (Neurology 59:1406-1411, 2002). RESULTS: Twenty-two patients were classified as having definite MD (9), probable MD (5), possible MD (6), or pyruvate dehydrogenase (PDH) deficiency (3), including one patient which showed a respiratory chain (RC) defect and PDH deficiency. Seven out of eight patients in whom significant RC defects were observed showed complex I defects. In 14 patients, epileptic seizures start at infantile ages. Of 17 patients who substantially presented generalized seizures, 4 patients started with partial seizures. Five patients consistently presented only partial seizures. The OGLST and UOA/PAA assays were useful for a more precise diagnosis of MD, although low positive predictive value of the OGLST was regrettable. No patient was classified as definite MD by Walker's original criteria, but the use of our revised MD criteria resulted in the classification of nine additional patients as definite MD. CONCLUSIONS: MD manifested considerable diverse epileptic phenotypes and should be considered in the differential diagnosis of epilepsy in children with unexplained encephalomyopathy and progressive and fluctuating clinical courses.  相似文献   
47.
The atypical antipsychotic risperidone is often prescribed to pediatric patients with neuropsychiatric disorders, though its effects on the developing brain remain unclear. Accordingly, we studied the effects of repeated treatment of risperidone on dopamine receptors in brain regions of juvenile rat. Levels of dopamine receptors (D(1), D(2), D(3), D(4)) in forebrain regions of juvenile rats were quantified after 3 weeks of treatment with three different doses of risperidone (0.3, 1.0 and 3.0 mg/kg) and compared findings to those in adult rats treated with risperidone (3.0 mg/kg/day) previously. Risperidone (at 1.0 and 3.0 mg/kg/day) increased levels of D(1) receptors in nucleus accumbens and caudate-putamen of juvenile, but not adult rats. Conversely, all three doses of risperidone dose-dependently increased D(2) labeling in medial prefrontal cortex and hippocampus, and D(4) receptor in nucleus accumbens, caudate-putamen and hippocampus of juvenile animals as well as in adults. Only the high dose of risperidone (3.0 mg/kg) increased D(2) receptors in caudate-putamen in both juvenile and adult brain. D(3) receptors were not altered by risperidone in any brain region at any dose or age. The findings indicate dose-dependent effects of risperidone on dopamine receptors in developing animals, and that juvenile animals are more sensitive than adults to the cerebral effects of risperidone.  相似文献   
48.
49.

Background  

Chronic plantar heel pain (CPHP) is one of the most common musculoskeletal disorders of the foot, yet its aetiology is poorly understood. The purpose of this study was to examine the association between CPHP and a number of commonly hypothesised causative factors.  相似文献   
50.
Insulin-like growth factor-1 (Igf-1), a critical mediator of tissue repair, is significantly decreased in diabetic wounds. Furthermore, decreased levels of hypoxia-inducible factor 1-alpha (Hif-1alpha) and its target genes are also associated with impaired wound healing in diabetic mice. The aim of our study was to examine whether the reduced levels of Igf-1 are responsible for the reduction in Hif-1alpha protein synthesis and activity in diabetic wounds. We provide evidence that Igf-1 regulates Hif-1alpha protein synthesis and activity during wound repair. In addition, Igf-1 stimulated phosphytidylinositol 3-kinase activity in diabetic fibroblasts, which, in turn, increased activation of the translational regulatory protein, p70 S6 kinase. Moreover, improved healing of diabetic wounds by addition of recombinant IGF-1 protein was associated with an increase in Hif-1alpha protein synthesis and function in vivo.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号